There is heightened awareness of fire prevention in homes and businesses in the United States. This awareness has led to the development of standards and legislation directed to reducing the risk of fires, particularly with respect to bedding and upholstered furniture. Conventional fire prevention techniques for bedding and upholstered furniture involve the topical application of flame retardant chemicals directly to an outer decorative layer of upholstery material.
However, recently passed legislation may render conventional fire protection techniques for bedding (particularly mattresses) inadequate. For example, the cigarette burn test for measuring flame resistance (developed by the Upholstered Furniture Action Council) has been deemed inadequate by the state of California and by the U.S. Consumer Product Safety Commission. In addition, new regulations being promulgated in some states prohibit the sale or manufacture of mattresses that do not pass these new flammability tests.
For example, California Technical Bulletin 603 of the State of California Department of Consumer Affairs (hereinafter “TB-603”), which is incorporated herein by reference in its entirety, exposes the top and side panels of a mattress to an open gas flame to simulate the effects of burning bedclothes. TB-603 is extremely aggressive relative to conventional cigarette burn tests and many industry analysts are skeptical that conventional upholstered furniture and bedding products (e.g., mattresses, etc.) will be able to pass TB-603.
In addition, material that can prevent the propagation of flame into the core cushioning material of furniture, and institutional bedding is desired. California Technical Bulletin 117 of the State of California Department of Consumer Affairs (hereinafter “TB-117”), which is incorporated herein by reference in its entirety, provides testing for upholstered furniture, and California Technical Bulletin 129 of the State of California Department of Consumer Affairs (hereinafter “TB-129”), which is incorporated herein by reference in its entirety, provides testing for institutional bedding.
In some cases, even though an upholstery fabric or ticking is constructed of inherently flame resistant material, it may be permeable such that heat and hot gases may be transmitted through the fabric causing internal materials to ignite. Furthermore, conventional methods of assembling mattresses and upholstered furniture may produce seams and joints that cannot withstand these new flammability tests without splitting open and subjecting flammable interior materials to flame. Also, pores formed in bedding fabrics as a result of sewing, seaming, quilting, and/or the attachment of labels, handles, decorations, vents, etc., may be penetrated by flames and hot gases which may result in the combustion of interior materials.
The top and side panels of a mattress are typically composed of layers of material. Typically the outer layer is a decorative ticking fabric that is a high quality knit or woven textile. The next layer is typically a cushioning layer, such as foam, batting, or other lofty, soft material. The cushioning layer provides a plump, soft, feel and texture to the panel. The next layer is typically a backing fabric that supports the cushioning material and provides strength and dimensional stability to the panel. The backing layer is conventionally a polyester or polypropylene nonwoven fabric, a knit, or a woven fabric. The layers of a mattress panel are typically assembled, for example, with stitch quilting, ultrasonic quilting, or are glued, bonded, heat bonded, or simply laid into a structure and attached at the seams. Conventionally, a flame and heat blocking component is added to the panel when the panel is designed to resist heat, fire, or ignition.
Mattress side and top panels typically are attached to panels underneath the mattress and/or atop a foundation that are commonly referred to as filler cloth. Filler cloth can be an alternative material to ticking fabric that is used for the top and sides of mattresses. Mattress construction may use filler cloth in various ways. For example, for mattresses that are not designed to be turned over, decorative fabric panels on the top and sides of the mattress are attached with a seam or a gusset. The side panel is drawn around the bottom of the mattress and attached to filler cloth by seaming. On the bottom of the mattress the seamed-in filler cloth is framed by the decorative side panel and does not extend to the edges of the mattress. This is commonly referred to as “continental” construction.
Also, for mattresses that are not designed to be turned over, a mattress may include a decorative top panel, a decorative side panel, and filler cloth on the bottom that is attached at the bottom edge of the mattress with a seam. Mattress foundations may utilize filler cloth in the top panel thereof.
To prevent the ignition of the core of a mattress, a variety of flame resistant materials have been utilized in the construction of mattress top and side panels. For example, fabrics made from graphite, carbon, para-aramid, or other flame and heat resistant fibers have been used. Batting composed of flame resistant fibers or fibers that char, such as silica-modified rayon (or Visil), modacrylic, FR rayon, FR polyester, melamine, or other suitable fibers may be produced that at high basis weights can provide flame resistance and insulation. Foams may be chemically treated with flame retardant or impregnated with graphite. Fabrics may also be treated with flame retardant and/or intumescent chemical compositions or impregnated with intumescent chemicals to provide flame blocking and insulative properties.
When designing a mattress for flame resistance, it has been common practice to place thick cushioning bats of flame resistant fiber, or fabrics composed of flame resistant fiber, or fabrics finished for flame redundancy, or fabrics coated with flame resistant or intumescent chemical, in the top and/or side panels where the major challenge of open flame is seen.
Unfortunately, when flame and heat resistance is achieved through the use of a batting of flame resistant fibers, the amount of batting material that is required to provide the flame resistance is significantly higher than the amount that would generally be needed to provide cushioning, texture, and aesthetics. In many cases, as much as twice the amount of fibrous batting is required to provide the flame resistance than is required to provide cushioning. While a normal amount of fibrous batting would be around 4 to about 6 ounces per square yard, 9 ounces per square yard, or more can be required for flame resistance. This has the consequences of forcing an “overstuffed” appearance, which may make sewing and construction difficult, and which may add significant costs to mattress construction.
In many mattress constructions, the cushioning and seaming of the mattress and foundation, can cause an opening in the fit between the two. This can be a design fault, or the design may result in the exposure of the filler cloth areas to the exterior of the mattress, mattress set, or sleep system. Additionally, mistakes in the actual construction of sleep systems, mattresses, or mattress sets can result in the exposure of the filler cloth areas. This exposure, can allow flame to penetrate to the area between the foundation and the mattress. Alternately, a mattress may be suspended on slats, spring wire, or other non-traditional foundation that would allow flames to directly contact the bottom of the mattress. When this happens, the filler cloth is exposed to the flame. If the filler cloth burns, or melts away, or shrinks away, then the flame can penetrate into the inside of the mattress side panel and propagate into the core of the mattress causing catastrophic failure.